Fuel tank

ABSTRACT

A fuel tank has a superior outer appearance. A body and a bottom are aligned to each other in a vertical direction to form a sealed closed space for storing fuel between both members. The body is formed as a container having an opening in a downward direction. A connected end part is bent inward in a continuous manner from a lower end of its outer surface. The opening is covered from below with the bottom and its circumferential edge is overlapped on the connected end while its position is set and connected at its entire circumference by brazing.

This application is a divisional of co-pending application Ser. No.09/019,987, filed on Feb. 6, 1998, the entire contents of which arehereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a fuel tank, and more particularly, toa fuel tank having a visually pleasing outer appearance for use on amotorized vehicle such as a motorcycle or motorbike.

2. Description of the Background Art

Japanese Patent Laid-Open No. Hei 6-47572 discloses a method formanufacturing a fuel tank for a motorized vehicle in which a body and abottom are aligned in the vertical direction to form a sealed space.Each of the body and the bottom is formed with an outwardly directedflange around the entire circumference. These outwardly directed flangesare overlapped with one another in the vertical direction, and areconnected together by a laser welding process.

Since the fuel tank for a motorized vehicle is frequently a visibleparts, it is preferable for the outwardly directed flange of the priorart to be arranged in such a way that it cannot be seen from the outsideas much as possible. However, in the case where the fuel tank isassembled by welding with a press melting method, such as seam weldingor laser welding, an outwardly directed flange becomes essential,although such an outwardly directed flange is projected toward an outercircumferential side of the fuel tank, making it quite difficult for theoutwardly directed flange to be prevented from being seen from theoutside.

SUMMARY OF THE INVENTION

In order to solve the aforesaid problems, the fuel tank of the presentinvention is made such that a body and a bottom are aligned with eachother in the vertical direction to form a sealed closed space, whereinthe body is formed as a container having an opening in a downwarddirection. An end part of the body encloses this opening, and is bentinwardly in a continuous manner from a lower end of its outer surface toform an entire circumferential connected end. A circumferential edge ofthe bottom is overlapped on the connected end and connected along itsentire circumference.

It is possible that a part of the connected end is formed at a portionbent back inwardly to be directed upward in a continuous manner from thelower end of the major outer appearance surface of the body. As oneexample of the connected end in this case, the lower end of the majorouter appearance surface of the body is bent back inwardly to form atapered shape in such a way that its extremity end is slanted upwardly.

The major outer appearance surface in this case is defined as a surfacewhich is most easily seen from outside in its applied form and appliedfor evaluation for outer appearance. In the case of the fuel tank for amotorized vehicle, for example, it is frequently found that the uppersurface, and both right and left side surfaces, may act as the majorouter appearance surface.

Further, in the present invention, it is possible to arrange a positionsetting means near the connected part between the connected end of thebody and the circumferential edge of the bottom. Additionally, theconnected end part of the body and the circumferential edge of thebottom can be connected by brazing or welding.

The end part of the body enclosing the opening section is bent inwardlyfrom a lower end section of an outer surface in a continuous manner toapply a connecting end of an entire circumference. The circumferentialedge part of the bottom is pushed against the connected end part frombelow the body and the circumferential edge of the body is connected tothe connected end part of the body at its entire circumference. Theresult is that the connected part is positioned at the lower side of thebody, and it is scarcely seen from outside, and the outer appearance isimproved.

In particular, when the connected part of the body is bent inwardly fromthe lower end of the major outer appearance surface in a continuousmanner to form a part bent back in an upward direction, the connectedpart between the connected end part of the body and the circumferentialedge part of the bottom is placed inside the major outer appearancesurface, and therefore it is not completely visible from outside. Theresult is that the outer appearance of the fuel tank is improved.

Further, when a position setting means is arranged near the connectedpart between the circumferential edge of the bottom and the connectedend part of the body, the connected end part of the body and thecircumferential edge of the bottom can be overlapped and connectedaccurately without using any particular jigs. Therefore, its workabilityis improved and an assembling facility can be simplified.

In addition, when the connected end part of the body and the connectedpart at the circumferential edge of the bottom are connected by brazingor welding, mere overlapping of the circumferential edge of the bottompart on the inwardly bent connected end of the body enables the weldingoperation to be carried out without press-contacting the welding partfrom each side, resulting in the connected end part of the body and thecircumferential edge part of the bottom being welded and connectedeasily and positively.

Further scope of applicability of the present invention will becomeapparent from the detailed description given hereinafter. However, itshould be understood that the detailed description and specificexamples, while indicating preferred embodiments of the invention, aregiven by way of illustration only, since various changes andmodifications within the spirit and scope of the invention will becomeapparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description given hereinbelow and the accompanying drawingswhich are given by way of illustration only, and thus, are notlimitative of the present invention, and wherein:

FIG. 1 is a cross-sectional side view of the fuel tank of the presentinvention;

FIG. 2 is a side elevational view showing an outer appearance of thefuel tank of the present invention;

FIG. 3 is a bottom view of the fuel tank of the present invention;

FIG. 4 is a cross-sectional view taken along line 4--4 of FIG. 2;

FIG. 5 is an expanded cross-sectional view taken along line 5--5 of FIG.3;

FIG. 6 is an expanded cross-sectional view taken along line 6--6 of FIG.3;

FIG. 7 is an expanded cross-sectional view taken along line 7--7 of FIG.3; and

FIGS. 8(A)-8(C) are schematic sectional views showing other preferredembodiments of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

One preferred embodiment of the invention will be described withreference to FIGS. 1 to 7. In these figures, the fuel tank of thepreferred embodiment is made such that a body 1 and a bottom member 2are connected in a vertical direction, and a sealed closed space forstoring fuel is formed between both members.

As shown in FIG. 4, the fuel tank has the form of a saddle, wherein aninverse U-shaped cavity 3 is formed at a central portion along thelongitudinal direction. A main frame pipe 4 constituting a body chassisframe of the motorized vehicle passes in the cavity along thelongitudinal direction.

Side tank chambers 5 located at the lower part of the fuel tank aredivided and formed at both right and left sides of the cavity 3 and arecontinuous with an upper chamber 6. The body 1 is formed as a containerhaving an opening 7 opening in a downward direction. Both right and leftside walls 8 and an upper wall 9 become the major visible outersurfaces.

In addition, a connected end part 12 defined by inwardly directedconnecting walls is bent in a substantial right angle in a continuousmanner from each of the lower ends of a front wall 10 and a rear wall 11of the outer surface toward a central part of the fuel tank, and fromeach of the right and left side walls 8. The opening defined byperipheral edges of the inwardly directed connecting walls of theconnected end part 12.

This connected end part 12 is formed continuously around an entireperiphery/circumference enclosing the opening 7. Both right and leftside walls 8 are formed such that extreme ends thereof are tapered andbent inside and slant upwardly of the fuel tank.

The bottom member 2 is formed as an inverted substantially U-shapedmember with a top part 13 and a vertical wall part 14 in a continuousmanner to cover the opening 7 from below, and to substantially cover theentire wall surface of the frame storing cavity 3. The peripheral edge15 of the bottom member 2 is overlapped at its entireperiphery/circumference on the peripheral edge of the inwardly directedconnecting walls forming the connected end part 12.

As shown in FIGS. 1, 5 and 6, the circumferential edge 15 is flat in itsforward and rearward ends and corner. A position setting projection 16protrudes therefrom in a plug-like manner near the extreme end of theconnected end 12.

In addition, both right and left side portions of the circumferentialedge part 15 are tapered sections extending in an outwardly opened anddownward direction to correspond with the connected ends 12 at bothtapered right and left sides of the body 1.

A brazing part 17 is formed between the connected end 12 and thecircumferential edge 15. Reference numeral denotes a bottom wall 18 ofthe side chamber 5 defined by the inwardly directed connecting wallsforming the connected end part 12.

When this fuel tank is assembled, the bottom member 2 is pushed frombelow against the body 1. The side part forms a tapered connectedsection where the connected end part 12 and the circumferential edge 15correspond to one another, thereby setting them in position in both theright and left directions, and overlapped.

The front-to-back placement of it is set in position by a method whereinthe position setting projection 16 contacts the extreme end of theconnected end 12 of the body. The connected end part 12 and thecircumferential edge 15 are set in position over their entireperiphery/circumference and overlapped with one another, and thus theopening 7 is covered by the bottom 2.

Under this condition, the entire circumferences of the overlappedsection between the connected end part 12 and the circumferential edge15 are welded by brazing. In this case, if each of the body 1 and thebottom 2 is made of iron, the brazing material is properly selected.

In the case of applying brazing material, the connected part cannot besupported from inside the fuel tank during the welding operation.However, even this structure can be connected without any problem byforming the connected end part in an inward direction.

However, in addition to brazing as the connecting method, other form ofconnection may be utilized. For example, welding by melting, such as arcwelding or gas welding can be applied, and adhesives may also beutilized.

As described above, since the connecting end 12 of the body is formedtoward an inside part of the fuel tank, the connected part between thecircumferential edge 15 of the bottom and the connected end 12 of thebody is scarcely seen from outside, because the bottom member 2 is fixedfrom below the opening 7.

In particular, since the connected end 12 is directed upward inside theouter appearance surface at both right and left side walls 8 forming themajor outer appearance surface of the fuel tank, the connected part withthe circumferential edge 15 of the bottom is placed inside the fuel tankand is not seen at all from the outside.

Accordingly, it is possible to remarkably improve the outer appearanceof the fuel tank, and this component becomes preferable as a fuel tankused as an outer appearance-based component, such as a fuel tank for amotorized vehicle.

In addition, as the position setting means, each of the circumferentialedge 15 and the connected end part 12 is tapered, and their taperedsections are aligned to each other. The position setting projection 16is provided so that the connected end 12 of the body and thecircumferential edge 15 of the bottom can be overlapped accurately andconnected. Thus, their workability can be improved and installation canbe simplified.

FIG. 1 shows additional elements which comprise the fuel tank, such as afeeding port cap 20, a filler tube 21, a separator 22, a breather tube23, a front body fixing stay 24, a small chamber plate 25, a fuel cockconnecting small chamber 26, a fuel cock fixing plug 27, and a rear bodyfixing stay 28.

FIGS. 8(A) to 8(C) are schematic cross-sectional views showing otherpreferred embodiments of the invention. FIG. 8(A) shows a connected end12 that does not face upward, but is instead bent inwardly at its entirecircumference. Also, the circumferential edge 15 of the bottom member 2is flat at its entire circumference in correspondence with it.

Even with such an arrangement as shown in FIG. 8(A), if the opening 7 iscovered from below with the bottom member 2 and at the same time theconnected end 12 and the circumferential edge 15 of the bottom areoverlapped at their entire circumferences while they are beingpositioned by the position setting projection 16, and they are connectedby the aforesaid proper method, the connected part is scarcely seen fromoutside, resulting in an outer appearance which is improved.

FIG. 8(B) shows an example where an inner wall 30 extends in a verticaldirection inside both right and left side walls 8 in the body 1 so as toform double inner and outer walls. The inner wall 30 is bent inward fromthe lower ends of both right and left side walls 8 in a continuousmanner to form a bottom part 31, where its extreme end side is bent backupward.

The connected end 12 is formed by bending the upper end of the innerwall 30. The opening 7 is opened downwardly into a deep concave space 32formed by the inner wall 30. The flat plate-like bottom member 2 islocated in the concave space 32 while its position is set at thesurrounding inner wall 30, the circumferential edge 15 overlaps theconnected end 12 and is connected there. With such an arrangement asshown in FIG. 8(B), since the connected end 12 is positioned at higherlocation than that of the lower ends of both right and left side walls 8acting as major outer appearance surfaces, the connected part betweenthe connected end 12 and the circumferential edge 15 is not seen at allfrom outside both right and left side walls 8, resulting in an outerappearance which is improved.

FIG. 8(C) is made such that the lower ends of both right and left sidewalls 8 are extended in a substantial horizontal inner direction to forma bottom part 31. The opening 7 is formed at its central part, with acircumferential edge of the bottom part 31 enclosing the opening 7, andenters an upper and inner location of the body 1 at a stepped part 33 ina stepwise manner to form the connected end 12.

The degree of step of the stepped part 33 in the bottom part 31 is aboutequal to the wall thickness of the bottom member 2. The bottom member 2is stored in the stepped part 33 while its position is set to locate thecircumferential edge 15 to be connected to the connected end 12, and theconnected part is not seen completely from outside.

The present invention is not limited to each of the aforesaid preferredembodiments, and various modifications can be attained. For example, theposition setting means may comprise any one of the taper-alignedstructures of the connected end 12 and the circumferential edge 15, theposition setting structure having the position setting projection 16, oran inner wall 30 or a stepped part 33.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art wereintended to be included within the scope of the following claims.

What is claimed is:
 1. A fuel tank for a vehicle comprising:a main tankmember having an upper wall, front and rear walls, right and leftsidewalls, and a bottom wall, said bottom wall having an opening thereindefined by inwardly directed connecting walls; and a bottom memberattached to said main tank member for sealing said opening, said bottommember having peripheral edges which overlap a portion of said inwardlydirected connecting walls around the entire periphery of said bottommember, wherein a central portion of said bottom member and all of saidperipheral edges of said bottom member lie in a single plane, saidbottom member is substantially flat, and said bottom member iscompletely flat over an entire surface of said bottom member.
 2. Thefuel tank according to claim 1, wherein said central portion of saidbottom member has a thickness, and said single plane lies completelywithin said thickness of said bottom member.
 3. The fuel tank accordingto claim 1, wherein a line extending across said upper wall from saidright sidewall to said left sidewall crosses no seams in said upperwall.
 4. The fuel tank according to claim 1, wherein said bottom memberis flat from one of said peripheral edges of said bottom member to everyother one of said peripheral edges of said bottom member.
 5. The fueltank according to claim 1, wherein said opening is spaced upwardly fromsaid bottom wall such that peripheral edges of the inwardly directedconnecting walls and said peripheral edges of said bottom member are notvisible when said fuel tank is viewed from the side.
 6. The fuel tankaccording to claim 1, further comprising interior sidewalls extending atleast partially upwardly from said bottom wall.
 7. The fuel tankaccording to claim 1, further comprising a stepped portion extending atleast partially upwardly and inwardly from said bottom wall, saidinwardly directed connecting walls being formed at interior portions ofsaid stepped portion.
 8. The fuel tank according to claim 1, whereinperipheral edges of the inwardly directed connecting walls are notvisible when said bottom member is attached to said main tank member. 9.A fuel tank for a vehicle comprising:a main tank member having an upperwall, front and rear walls, right and left sidewalls, and a bottom wall,said bottom wall having an opening therein defined by inwardly directedconnecting walls; and a bottom member attached to said main tank memberfor sealing said opening, said bottom member having peripheral edgeswhich overlap a portion of said inwardly directed connecting wallsaround the entire periphery of said bottom member, wherein a centralportion of said bottom member and all of said peripheral edges of saidbottom member lie in a single plane, said bottom member is substantiallyflat, and said bottom member is flat over an entire surface of saidbottom member from one of said peripheral edges of said bottom member toevery other one of said peripheral edges of said bottom member.
 10. Thefuel tank according to claim 9, wherein said central portion of saidbottom member has a thickness, and said single plane lies completelywithin said thickness of said bottom member.
 11. The fuel tank accordingto claim 9, wherein said opening is spaced upwardly from said bottomwall such that peripheral edges of the inwardly directed connectingwalls and said peripheral edges of said bottom member are not visiblewhen said fuel tank is viewed from the side.
 12. The fuel tank accordingto claim 11, further comprising interior sidewalls extending at leastpartially upwardly from said bottom wall.
 13. The fuel tank according toclaim 11, further comprising a stepped portion extending at leastpartially upwardly and inwardly from said bottom wall, said inwardlydirected connecting walls being formed at interior portions of saidstepped portion.